Grevillea rhyolitica

Sometimes sold with the cultivar-like name: Grevillea 'Deua Flame'

Deua Flame

Grevillea
rhyolitica, commonly known as the Deua Flame, is one of over 350 Grevilleas
belonging to the family Proteaceae. It has been classified as a Rare or Threatened
Australian Plant (ROTAP) due to its restricted range. It occurs naturally in
the sub coastal montane areas of the NSW south coast, from NW to SW of Moruya
in the Dampier State Forest and Deua National Park.

The
subspecies rhyolitica is a spreading shrub, growing up to 2m in height.
This form has the wider range, occurring naturally in moist gullies and steep
ridges, from open forests and shrublands, to riparian forests. It occurs on
skeletal soils on rhyolite rocks.

The subspecies semivestita is a dense, rounded shrub approximately 1x1m
in size. It occurs in coastal mountain ranges, in skeletal soils on steep upper
slopes, below rock outcrops of rhyolite.

The subspecies semivestita is more desirable horticulturaly due to its
dense, compact size, and almost continuous flowering period. It’s brilliant
red flower heads produce abundant nectar so will attract a variety of nectar-eating
birds to the garden. This form prefers a relatively sunny aspect, however, will
tolerate shade. It is also frost and coast tolerant, making it suitable for
a range of garden conditions throughout the country.

Maintenance in the form of fertilising is unnecessary as it is adapted to low
levels of soil nutrients. Regular pruning is required as this will encourage
dense growth and increase flowering.

The preferred method of propagation for G. rhyolitica is by cuttings.
This is standard for most grevilleas as seed is rarely available and often poses
difficulties in germination. Cuttings have a high strike rate and begin flowering
earlier than plants grown from seed.

In order to maintain a healthy garden plant, the conditions must be suitable
for propagation. G. rhyolitica requires a well-drained garden bed, with
coarse, slightly acidic soil. Borers and scale insects are common pests to grevilleas
and can cause considerable damage, leading to death if left unchecked. A minor
effect of scale infestation is the growth of black sooty mould. This looks unsightly
but is relatively harmless. In some regions of Australia Phytopthera and
other diseases threaten both wild and cultivated populations. Most pests can
be treated with commercial pesticides.

Grevillea rhyolitica has been available for cultivation since the early
1990’s. It has high potential for hybridization with other grevillea species.

Text by Kate Alexander (Botanical Intern 2003)

Derivation of scientific name:
Grevillea rhyolitica

Grevillea- after C.F. Greville (1749-1809), a patron of botany
and president of the Royal Society of London.

rhyolitica- refers to the occurrence of this species on outcrops
of rhyolite rock.